That was far better than the other two episodes this year. Wasn't a massive fan of the cliffhanger, I was thinking that it could just be an associate too, but the scene after the credits was Moriarty himself not just an image, so that makes me think that they are going to bring him back (twin brother perhaps?).
Not sure about that. If they do bring him back then the end of season 2 just seems like a waste really. If they do bring him back they probably won't explain how he faked blowing his brains out, they'll just let the fans come up with theories and then film a few of those and say, 'take your pick'.